How many significant figures does $00.0687400$ have?
Explanation: Identify the non-zero digits and any zeros between them. These are all significant. $00.0{6874}00$ Leading zeros are not significant. $\color{orange}{00.0}{6874}00$ Since there is a decimal, trailing zeros are significant. $\color{orange}{00.0}{687400}$ Counting all the significant digits gives us 6.